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<html>
  <head>
    <meta charset='utf-8'>
    <meta name='viewport' content='width=device-width, initial-scale=1, user-scalable=no'>
    <meta name='mobile-web-app-capable' content='yes'>
    <meta name='apple-mobile-web-app-capable' content='yes'>
    <link rel='icon' type='image/png' sizes='32x32' href='favicon-32x32.png'>
    <link rel='icon' type='image/png' sizes='96x96' href='favicon-96x96.png'>
    <link rel='stylesheet' href='css/common.css'>

    <title>Stereo Video Player</title>
  </head>
  <body>
    <header>
      <details open>
        <summary>Stereo Video Player</summary>
        <p>
          This sample demonstrates how to play a stereo 3D video.
          <a class="back" href="./">Back</a>
          <br/>
          <hr/>
          Autoplay when VR starts: <input id='autoplayVideo' type='checkbox'/>
        </p>
      </summary>
    </header>
    <script type="module">
      import {WebXRButton} from './js/util/webxr-button.js';
      import {Scene} from './js/render/scenes/scene.js';
      import {Renderer, createWebGLContext} from './js/render/core/renderer.js';
      import {UrlTexture} from './js/render/core/texture.js';
      import {ButtonNode} from './js/render/nodes/button.js';
      import {Gltf2Node} from './js/render/nodes/gltf2.js';
      import {VideoNode} from './js/render/nodes/video.js';
      import {InlineViewerHelper} from './js/util/inline-viewer-helper.js';
      import {QueryArgs} from './js/util/query-args.js';

      // If requested, use the polyfill to provide support for mobile devices
      // and devices which only support WebVR.
      import WebXRPolyfill from './js/third-party/webxr-polyfill/build/webxr-polyfill.module.js';
      if (QueryArgs.getBool('usePolyfill', true)) {
        let polyfill = new WebXRPolyfill();
      }

      let autoplayCheckbox = document.getElementById('autoplayVideo');

      // XR globals.
      let xrButton = null;
      let xrImmersiveRefSpace = null;
      let inlineViewerHelper = null;

      // WebGL scene globals.
      let gl = null;
      let renderer = null;
      let scene = new Scene();
      scene.addNode(new Gltf2Node({url: 'media/gltf/home-theater/home-theater.gltf'}));
      scene.enableStats(false);

      let video = document.createElement('video');
      video.loop = true;
      video.src = 'media/video/bbb-sunflower-540p2-1min.webm';

      let videoNode = new VideoNode({
        video: video,
        displayMode: 'stereoTopBottom'
      });

      // When the video is clicked we'll pause it if it's playing.
      videoNode.onSelect(() => {
        if (!video.paused) {
          playButton.visible = true;
          video.pause();
        } else {
          playButton.visible = false;
          video.play();
        }
      });
      videoNode.selectable = true;

      // Move back to the position of the in-room screen and size to cover it.
      // Values determined experimentally and with many refreshes.
      videoNode.translation = [0.025, 0.275, -4.4];
      videoNode.scale = [2.1, 1.1, 1.0];
      scene.addNode(videoNode);

      video.addEventListener('loadeddata', () => {
        // Once the video has loaded up adjust the aspect ratio of the "screen"
        // to fit the video's native shape.
        let aspect = videoNode.aspectRatio;
        if (aspect < 2.0) {
          videoNode.scale = [aspect * 1.1, 1.1, 1.0];
        } else {
          videoNode.scale = [2.1, 2.1 / aspect, 1.0];
        }
      });

      // Add a button to the scene to play/pause the movie.
      let playTexture = new UrlTexture('media/textures/play-button.png');

      // Create a button that plays the video when clicked.
      let playButton = new ButtonNode(playTexture, () => {
        // Play the video and hide the button.
        if (video.paused) {
          playButton.visible = false;
          video.play();
        }
      });
      // Move the play button to the center of the screen and make it much
      // bigger.
      playButton.translation = [0.025, 0.275, -4.2];
      playButton.scale = [5.0, 5.0, 5.0];
      scene.addNode(playButton);

      function initXR() {
        xrButton = new WebXRButton({
          onRequestSession: onRequestSession,
          onEndSession: onEndSession
        });
        document.querySelector('header').appendChild(xrButton.domElement);

        if (navigator.xr) {
          navigator.xr.isSessionSupported('immersive-vr').then((supported) => {
            xrButton.enabled = supported;
          });

          navigator.xr.requestSession('inline').then(onSessionStarted);
        }
      }

      function initGL() {
        if (gl)
          return;

        gl = createWebGLContext({
          xrCompatible: true
        });
        document.body.appendChild(gl.canvas);

        function onResize() {
          gl.canvas.width = gl.canvas.clientWidth * window.devicePixelRatio;
          gl.canvas.height = gl.canvas.clientHeight * window.devicePixelRatio;
        }
        window.addEventListener('resize', onResize);
        onResize();

        renderer = new Renderer(gl);
        scene.setRenderer(renderer);
      }

      function onRequestSession() {
        let autoplay = autoplayCheckbox.checked;

        let pending;

        if (autoplay) {
          // If we want the video to autoplay when the session has fully started
          // (which may be several seconds after the original requestSession
          // call due to clicking through consent prompts or similar) then we
          // need to start the video within a user activation event first
          // (which this function is.) Once it's been started successfully we
          // pause it, at which point we can resume it pretty much whenever we'd
          // like.
          pending = video.play().then(() => {
            video.pause();
          });
        }

        return navigator.xr.requestSession('immersive-vr', {
            requiredFeatures: ['local-floor']
        }).then((session) => {
          xrButton.setSession(session);
          session.isImmersive = true;
          onSessionStarted(session);

          if (autoplay) {
            pending.then(() => {
              video.play();
            });
          }
        });
      }

      function onSessionStarted(session) {
        session.addEventListener('end', onSessionEnded);
        session.addEventListener('select', (ev) => {
          let refSpace = ev.frame.session.isImmersive ?
                           xrImmersiveRefSpace :
                           inlineViewerHelper.referenceSpace;
          scene.handleSelect(ev.inputSource, ev.frame, refSpace);
        });

        initGL();
        scene.inputRenderer.useProfileControllerMeshes(session);

        let glLayer = new XRWebGLLayer(session, gl);
        session.updateRenderState({ baseLayer: glLayer });

        // In this case we're going to use an 'local' frame of reference
        // because we want to users head to appear in the right place relative
        // to the center chair, as if they're sitting in it, rather than
        // somewhere in the room relative to the floor.
        let refSpaceType = session.isImmersive ? 'local' : 'viewer';
        session.requestReferenceSpace(refSpaceType).then((refSpace) => {
          if (session.isImmersive) {
            xrImmersiveRefSpace = refSpace;
          } else {
            inlineViewerHelper = new InlineViewerHelper(gl.canvas, refSpace);
          }

          session.requestAnimationFrame(onXRFrame);
        });
      }

      function onEndSession(session) {
        session.end();
      }

      function onSessionEnded(event) {
        if (event.session.isImmersive) {
          xrButton.setSession(null);
          video.pause();
        }
      }

      function onXRFrame(t, frame) {
        let session = frame.session;
        let refSpace = session.isImmersive ?
                         xrImmersiveRefSpace :
                         inlineViewerHelper.referenceSpace;
        let pose = frame.getViewerPose(refSpace);

        scene.startFrame();

        session.requestAnimationFrame(onXRFrame);

        scene.updateInputSources(frame, refSpace);

        scene.drawXRFrame(frame, pose);

        scene.endFrame();
      }

      // Start the XR application.
      initXR();
    </script>
  </body>
</html>
